Vatican City ? The Vatican Saturday denounced feminism for trying to blur differences between men and women and threatening the institution of families based on a mother and a father.

The drive for equality makes “homosexuality and heterosexuality virtually equivalent, in a new model of polymorphous sexuality,” the Vatican said.

The concerns, raised in a 37-page document written by one of Pope John Paul II’s closest aides, broke no new ground, maintaining the Roman Catholic Church’s ban on women priests, for example.

But some observers said they feared how the document might be used.

Professor Paul Lakeland, a church expert at Fairfield University in Connecticut, said the paper could be used by church conservatives to condemn any form of advocacy for women.

“The irony is that this document is, in some respect, a feminist document,” Lakeland said, pointing to references to fair treatment of women who work.

The pamphlet by Cardinal Joseph Ratzinger, the Vatican’s orthodoxy watchdog, was published during a Vatican campaign to protect what it terms the Christian family. Earlier salvos have blasted same-sex marriage and appealed to politicians, regardless of their religion, to prevent such unions from winning legal recognition.

The document, addressed to bishops worldwide, contended that new recent approaches to women’s issues were marked by a tendency “to emphasize strongly conditions of subordination in order to give rise to antagonism: women, in order to be themselves, must make themselves the adversaries of men.”

Such an attitude, the document said, “has its most immediate and lethal effects in the structure of the family.”

Pope John Paul II, flanked by altar boys, blesses the faithful during the weekly general audience in the Paul VI Hall at the Vatican. A top adviser to the pope, who opposes women in the priesthood, wrote a letter to bishops blaming feminism for blurring distinctions between men and women.

The document also said that feminism wrongly tended to deny the differences between men and women “in order to avoid the dominance of one sex or the other.”

The consequences of obscuring the differences between men and women, it said, included calling “into question the family, in its natural two-parent structure of mother and father,” giving homosexual and heterosexual couples an equivalent status.

The document also took issue with a “certain type of feminist rhetoric” that makes “demands ‘for ourselves.”‘

Throughout John Paul’s 25 years as pope, he repeatedly has expressed his admiration for women and their talents, and the document reflected that.

It said women should not be stigmatized or penalized financially for wanting to be homemakers. It also said women “should be present in the world of work and … have access to positions of responsibility which allow them to inspire the politics of nations and to promote innovative solutions to economic and social problems.”

Those who choose to work should be granted an appropriate work schedule and “not have to choose between relinquishing their family life or enduring continual stress,” the message to bishops said.

The Rev. Thomas Reese, a commentator on the Catholic Church, said in an e-mailed statement that “although most American feminists would express their theology differently from the Vatican, on the practical level, they are on the same page (in terms of equality in education, politics, workplace) except on abortion and women priests.”

Catholic teaching forbids abortion.

“While most people in the U.S. think in psychological and sociological terms, the Vatican thinks and talks in philosophical and theological terms which most Americans find difficult to understand,” said Reese, editor of America, a Jesuit magazine.